Metal wrapped non-metallic magnetic component for use about a rotor or the like and method of making the same

ABSTRACT

A system of manufacturing a metal wrapped non-metallic magnetic component useable about a rotor or the like comprises welding the ends of a strip of sheet metal to form a cylinder. If necessary, the cylinder may be cut about its entire circumference at two axial locations thereby isolating a central portion of the cylinder having exposed a first axial end and a second axial end. The cylinder is then form rolled to deform the first and second axial ends radially inward to form a channel located along the inner diameter. The magnetic material may then be inserted within the channel between a deformed first and second axial ends of the central cylindrical portion. The central cylindrical portion may then be form rolled such that the flanges are folded about the ends of the magnetic material.

BACKGROUND OF THE INVENTION

This invention relates to the field of magnetic rotors and shafts usedto impart a rotating magnetic field and, more particularly, to a metalwrapped non-metallic magnetic rotor and method of making the same.

Various machines commonly require a rotating magnetic field in order tofunction as intended. For example, electric motors or magnetic drivescommonly utilize magnetic rotors in their operation. One technique formagnetizing a rotor is to manufacture the rotor itself out of a magneticmaterial. However, it is also possible to manufacture the rotor out of ametallic material and affix a magnetic material, such as a magnetizedplastic, on the outer diameter of the rotor to impart magneticproperties.

It is therefore an object of the present invention to provide a metalwrapped non-metallic magnetic component capable of use about a rotorand/or shaft to magnetize the rotor and/or shaft.

It is also an object of the present invention to provide an efficientmethod of making a metal wrapped non-metallic magnetic component capableof use about a rotor and/or shaft.

SUMMARY OF THE INVENTION

The aforementioned objects may be achieved through use of the metalwrapped non-metallic magnetic component and method of making the same.The method comprises welding the ends of a predetermined strip of metalto form a cylinder of metal, form rolling the cylinder to deform a firstaxial end and a second axial end thereof radially inward to form achannel located along the inner diameter of the cylinder defined betweena first and second flange formed by the deformed first and second axialends and a middle part of the cylinder, inserting the magnetic materialwithin the channel wherein the outer diameter of the magnetic materialcontacts the inner diameter of the cylinder between the deformed firstand second axial ends of the central cylindrical portion, form rollingthe central cylindrical portion such that the flanges are folded aboutthe ends of the magnetic material to contact an inner diameter of themagnetic material thereby forming a metal wrapped non-metallic magneticcylindrical component. After welding the ends of the strip of metaltogether, the cylinder may be cut about its entire circumference at twoaxial locations thereby isolating a portion of the cylinder havingexposed the first axial end and second axial end.

Form rolling the cylinder to deform the axial ends thereof radiallyinward to form a channel located along the inner diameter of thecylinder between a first and second flange formed by the deformed axialends may be achieved by form rolling the cylinder to deform the existingends thereof radially inwards at a first angle, and form rolling thecylinder to deform the axial ends thereof from a first angle to a secondangle wherein the flanges are formed by the deformed existing endsextend radially inward and substantially perpendicular from theremaining portion of the cylinder.

Form rolling the cylinder so that the flanges are folded about the endsof the magnetic material may be achieved by form rolling the cylinder todeform the flanges into an intermediate position, and form rolling thecylinder to deform the flanges from the intermediate position to a finalposition wherein the flanges are folded about the ends of the magneticmaterial such that the outer tips of the flanges are substantiallyparallel with the middle part of the cylinder.

Form rolling the cylinder to deform the existing ends thereof radiallyinwards at a first angle may be achieved by form rolling during a firstrolling stage. A first bottom form rolls and a first top form rolls maybe used to perform the first rolling stage.

Form rolling the cylinder to deform the existing ends thereof to asecond angle may be achieved by form rolling the cylinder during asecond rolling stage. A second top form rolls and a second bottom formrolls may be used to perform the second rolling stage.

Form rolling the cylinder such that the flanges are folded about theends of the magnetic material into an intermediate position may beachieved by form rolling in a third rolling stage. A third bottom formrolls and a third top form rolls may be used to perform the thirdrolling stage.

Form rolling the cylinder such that the flanges are folded about theends of the magnetic material in a final position may include formrolling the cylinder portion during a fourth rolling stage. A fourthbottom form rolls and a third top form rolls may be used to perform thefourth rolling stage.

The form rolling stages are performed using a form rolling machine.Welding the ends of a predetermined strip of sheet metal may beperformed by welding the ends of a strip of stainless steel.

The invention also incorporates a metal wrapped non-metallic magneticcomponent useable about a rotor or the like which includes a strip ofsheet metal having its ends welded together to form a cylinder of sheetmetal having a first and second axial end. The cylinder may be formrolled to form a channel defined by the inner diameter of the centralcylindrical portion and a first and second flange formed by formrolling. The channel has a non-metallic magnetic material insertedtherein, the magnetic material being secured within the channel by formrolling the central cylindrical portion such that the flanges are foldedabout the ends of the magnetic material to contact an inner diameter ofthe magnetic material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an isometric view of a form rolling apparatus useable formaking a metal wrapped non-metallic magnetic component for use on arotor or the like in accordance with the principles of the presentinvention;

FIG. 2 depicts a sectional view of a cylindrically shaped metal wrappednon-metallic magnetic component mountable on a rotor manufactured inaccordance with the principles of the present invention;

FIG. 3 depicts an isometric view of a cylindrically shaped piece ofmetal, steel, foil, or the like after being welded in accordance withthe principles of the present invention;

FIG. 4 depicts a front view of the form rolling apparatus depicted inFIG. 1;

FIG. 5 depicts a sectional view of upper and lower form rolls mounted onthe form rolling apparatus to perform a first rolling stage used inmaking the metal wrapped non-metallic magnetic component in accordancewith the principles of the present invention;

FIG. 6 depicts a sectional view of another set of upper and lower formrolls mounted on the form rolling apparatus to perform a second rollingstage used in making the steel wrapped non-metallic magnetic componentin accordance with the principles of the present invention;

FIG. 7 depicts a sectional view of another set of upper and lower formrolls mounted on the form rolling apparatus to perform a third rollingstage used in making the steel wrapped non-metallic magnetic componentin accordance with the principles of the present invention; and

FIG. 8 depicts a sectional view of another set of upper and lower formrolls mounted on the form rolling apparatus to perform a fourth rollingstage used in making the steel wrapped non-metallic magnetic componentin accordance with the principles of the present invention.

DETAILED DESCRIPTION

Referring to FIG. 2, a portion of a metal wrapped non-metallic magneticcylindrically shaped component 1 mountable on a rotor, shaft or the likeis shown. The component 1 contains a metal shell 3, preferably made ofstainless steel or some other sheet metal, wrapped about a non-metallicmagnetic material 2 such as a magnetized plastic.

The component is manufactured using a form rolling machine such as thetype depicted in FIG. 1. The form rolling machine, generally denoted 4contains a pair of vertical machine columns 12, 13 on both sides of anupper roll housing 14 and lower roll housing 16. The upper roll housing14 contains an upper roll shaft 17 extending therethrough, and the lowerroll housing 16 contains a lower roll shaft 18 extending therethrough.One of the machine columns 12 contains a guide means 20 which ispivotable and slidable relative to the machine column 12. The upper rollhousing 14 is connected to a hand wheel 22 by means of a lead screw 24threaded through a top plate 26. Rotation of the hand wheel turns thelead screw, which is rotatable relative to the upper roll housing 14,and therefore varies the height of the upper roll housing relative tothe lower roll housing 16. The upper roll shaft 17 and lower roll shaft18 are each connected to a drive means which rotates the shafts inopposite directions. Various types of drive means may suffice so long asthe upper roll shaft 17 rotates in a direction opposite to the lowerroll shaft 18. Universal joints 26, 27 are incorporated on the upperroll shaft 17 to allow the shaft to move vertically while rotating.Although not shown, the lower roll shaft 18 may also contain one or moreuniversal joints.

The roll shafts 17, 18 are capable of supporting form rolls 30, 32 whichmay be affixed to the upper and lower roll shafts 17, 18 and rotatedwith the shaft. The form rolls comprise one or more disks having acircumference formed by a particular shaped outer diameter. Upper andlower form rolls are capable of being moved vertically relative to oneother by manipulation of the hand wheel 22 which raises and lowers theupper roll housing 14 and upper roll shaft 17 (containing a top roll32). The component 1 is manufactured in a series of form rolling stages.Each rolling stage involves the deformation of the metal cylinder 3between a different combination of form rolls mounted on the upper andlower roll shafts 17, 18. Although one type of form rolling machine isdiscussed herein, it is apparent to one skilled in the art that othertypes of form rolling machines may suffice for use with the principlesof the present invention.

The component may be made by welding a predetermined length, or strip,of steel together to form the cylindrical, or ring-shaped, member 3.Preferably, stainless steel may be used. However, other types ofnon-magnetic materials such as aluminum, etc. may suffice. Referring nowto FIG. 3, the respective ends of the strip of metal may be weldedtogether using any conventional welding technique to form the cylinder3. For example, securing the metal in a copper clamping fixture andwelding with a Linde Plasma Needle Arc Welder will suffice. However, theweld 5 may not extend across the entire surface of the cylinder. If thisoccurs, the resulting metal cylinder 3 may be cut about itscircumference in two axial locations 7, 9 such that the ends of thecylinder which extend past the weld 5 are cut from a remaining centralportion of the cylinder. This cutting is performed at the axiallocations 7, 9 which correspond to the ends of the weld 5 such that theremaining portion 6 of the cylinder has the weld 5 extending throughout.The weld 5 should extend throughout the length of the cylinder toprovide the cylinder with the optimum structural stability.

The metal cylinder 3 may then be form rolled. The cylinder 3 is thenplaced between a first upper roll and first lower roll to be form rolledin a first stage on the form rolling machine depicted in FIG. 1. FIG. 5depicts a sectional view of the interface between the first upper roll30 and the first lower roll 32, and the metal cylinder 3 mountedtherebetween, mounted on the form rolling machine 4. The cross-sectionof the first upper roll 30 and first lower roll 32 are configured asshown in FIG. 5. The first bottom roll 32 is mounted on the lower rollshaft 18 and the first upper roll 30 is mounted on the upper roll shaft17. The metal cylinder 3 is supported by the lower form rolls 18 andguide means 20 (see FIG. 4). As shown in FIG. 4, the guide means 20contains a roller 120 which is slidable relative to machine column 12 bymeans of a bracket 122 having a screw fastener 123 inserted into thecolumn 12 through a groove 124 in the bracket. The roller may be mountedon the inside or outside of the metal cylinder 3 in order to allow themetal cylinder 3 to maintain proper shape and form.

Referring again to FIG. 5, the cross-section of the metal cylinder 3 isinitially flat shaped when mounted on the lower roll 32 between endflanges 34 and 36. The lower roll is mounted between the end flanges.The drive means is activated such that the rolls 30, 32 rotate the handwheel 22 is turned in the clockwise direction to lower the upper rollhousing 14, 30 and thereby lower the upper roll 30 into the positionsubstantially shown in FIG. 5. By gradually lowering the upper roll 30while the rolls 30, 32 are rotating, the shape of the metal cylinder 3,which also rotates between the rolls 30, 32, will be deformed into thecross-sectional configuration shown in FIG. 5. After the upper roll 30has been lowered to its lowermost point (i.e., where no further loweringof the upper roll by the hand wheel is possible) the cross-section ofthe metal cylinder 3 will be shaped as shown in FIG. 5 and the firstrolling stage completed.

Using the form rolling apparatus of FIG. 1 in a manner similar to itsuse in the first rolling stage, a second rolling stage may be performedusing a second top roll 38 and a second bottom roll 40. FIG. 6 depictsthe second top roll 38 and second bottom roll 40 useable in the secondrolling stage. The second top roll 38 contains a pair of end portions41, 43 having a radius of curvature 42 which is typically fifteen tenthsof the length of the radius of the metal cylinder 3. The metal cylinder3 is mounted on the lower roll 40. By gradually lowering the second toproll 38 using the hand wheel 22 while the drive means rotates the rolls38, 40, the second top roll 38 is lowered onto the second bottom roll 40and the axial ends of the metal cylinder are deformed such that theyform flanges 44, 46 which extend radially towards the bottom roll shaftand are perpendicular with the remaining portion of the metal cylinder.After the second top roll 38 is gradually lowered to its lowestposition, the metal cylinder 3 will be configured as shown in FIG. 6 andthe second rolling stage completed. After the second rolling stage iscompleted, the metal cylinder 3 will have a channel 8 extending alongits inner diameter defined by the flanges 44, 46 which extend from themiddle portion thereof.

After the second rolling stage is completed, the magnetic material maythen be inserted into the channel 8 to form the component 1. The lengthof the magnetic material may be obtained by the following equation:

    L.sub.m =(D.sub.s +T.sub.m)·π·1.005

where:

L_(m) =Length of magnet material;

D_(s) =Diameter of shaft on which the completed component will bemounted;

T_(m) =Thickness of magnet strip;

π=3.1416;

The resultant length will provide extra material compression wheninserted into the channel 8 of the metal cylinder 3. The optimum lengthof plastic magnetic material may be determined by trial fitting todetermine a length whch will be snugly compressed without buckling asthe third and fourth rolling stages are performed. When used on a rotor,it will be desired to make the component slightly smaller than the rotorto assure a tight fit of the assembled component, said tight fit beingaffected by the amount of plastic material fitted into the cylinder 3.

After the second rolling stage has been completed and the magneticmaterial 2 inserted into the channel 8, the metal cylinder 3 may berolled in a third rolling stage. A third top roll 48 and third bottomroll 50 are affixed to the upper roll shaft 17 and lower roll shaft 18,respectively, to perform this rolling stage. FIG. 7 depicts the thirdtop roll 48 and third bottom roll 50. The metal cylinder 3 is mounted onthe bottom roll 50. By gradually lowering the third top roll 48 usingthe hand wheel 22, the third top roll 48 is lowered onto the thirdbottom roll 50. The axial ends of the metal cylinder are thereforedeformed such that flanges 44, 46, which extended radially towards thebottom roll shaft and perpendicular with the remaining portion of themetal cylinder, are deformed into an intermediate position (shown inFIG. 7). After the third top roll 38 is gradually lowered to its lowestposition, the metal cylinder 3 will be deformed into the shape shown inFIG. 7 and the third rolling stage completed. The flanges 44, 46 will bepositioned at an angle of less than ninety degrees relative to the innerdiameter of the magnetic material 2.

After the third rolling stage, a fourth rolling stage may be performedon the form rolling apparatus 4 using a fourth top roll 52 and a fourthbottom roll 54. FIG. 8 depicts the fourth top roll 52 and fourth bottomroll 54 useable in the fourth rolling stage. The metal cylinder 3 andmagnetic material 2 are mounted on the fourth bottom roll 54. By turningthe hand wheel 22 while the drive means rotates the rolls 52, 54, thefourth top roll 52 is gradually lowered onto the fourth bottom roll 54and the axial ends of the metal cylinder are deformed such that flanges44, 46 substantially parallel with the inner diameter of the magneticmaterial 2. After the fourth top roll is lowered to its lowest positiononto the fourth bottom roll 54 and the rolls are spun by the drivemeans, the metal cylinder 3 will be as shown in FIG. 8 and the fourthrolling stage will be complete.

Each form rolling stage is performed by placing the cylinder 3 (andmagnetic material if at the appropriate stage) on the lower roll. Thetop roll is then lowered to initially contact the outer diameter of themetal cylinder. The form rolling machine is activated such that theupper and lower shaft 17, 18 rotate thereby rotating the upper and lowerform rolls. The rotation of the upper and lower form rolls will alsorotate the metal cylinder 3 which is guided by the guide means 20 androller 120. By gradually lowering the upper roll via the hand wheel 22while the form rolls are rotating, the metal cylinder will deform into ashape which is dictated by the position of the upper and lower formrolls.

The upper and lower form rolls depicted in the drawings are comprised ofone piece members. However, it will be apparent to one skilled in theart that the form rolls may be comprised of a plurality of discs whichmay be placed side by side on the upper or lower roll shafts 17, 18 toresult in the desired cross-sectional configuration of the form rollsnecessary to perform the first through fourth form rolling stages. Also,it will be apparent to one skilled in the art that additional orintermediate rolling stages not depicted herein may also be performed.

After the fourth rolling stage has been completed, the resultantstructure will comprise the component depicted in FIG. 2 which may bemounted about a shaft or the like to impart magnetic properties thereto.

Although the invention has been described in connection with theembodiments depicted herein, the invention is not intended to be limitedto these particular embodiments. Various modifications, changes andequivalents may be incorporated into these embodiments and are intendedto be within the scope of the invention as defined by the followingclaims.

What is claimed is:
 1. A method of manufacturing a metal wrappednon-metallic magnetic component useable about a rotor comprising: thesteps ofwelding ends of a strip of sheet metal thereby forming acylinder of metal; form rolling the cylinder thereby deforming a firstaxial end and a second axial end thereof radially inward into a firstand second flange, and thereby forming a channel located along an innercircumference of the cylinder defined by the deformed first and secondaxial ends and a central part of the cylinder; inserting magneticmaterial within the channel wherein an outer circumference of themagnetic material contacts the inner circumference of the cylinderbetween the deformed first and second axial ends; and form rolling thecylinder such that the flanges are folded about ends of the magneticmaterial thereby contacting an inner circumference of the magneticmaterial with the folded flanges, and thereby forming a metal wrappednon-metallic magnetic cylindrical component.
 2. The method of claim 1wherein form rolling the cylinder to deform the first and second axialends thereof radially inward to form a channel located along the innercircumference of the cylinder comprises:form rolling the cylinder,thereby deforming the first and second axial ends radially inward at afirst angle; and form rolling the cylinder, thereby deforming the firstand second axial ends thereof from the first angle to a second anglewherein the flanges formed by the deformed first and second axial endsextend radially inward substantially perpendicular to the remainingportion of the cylinder.
 3. The method of claim 2 wherein form rollingthe cylinder so that the flanges are folded about the ends of themagnetic material comprises:form rolling the cylinder, thereby deformingflanges into an intermediate position; and form rolling the cylinder,thereby deforming flanges from the intermediate position to a finalposition wherein the flanges are folded about the ends of the magneticmaterial such that the flanges are substantially parallel with a middlepart of the cylinder.
 4. The method of claim 3 wherein form rolling thecylinder to deform the first and second axial ends thereof radiallyinwards at a first angle comprises form rolling during a first rollingstage.
 5. The method of claim 4 further comprising using a first bottomform roll and a first top form roll to perform the first rolling stage.6. The method of claim 5 wherein form rolling the cylinder to deformexisting ends thereof to a second angle comprises form rolling thecylinder during a second rolling stage.
 7. The method of claim 6 furthercomprising using a second top form roll and a second bottom form roll toperform the second rolling stage.
 8. The method of claim 7 wherein formrolling the cylinder such that the flanges folded about the ends of themagnetic material into an intermediate position comprises form rollingduring a third rolling stage.
 9. The method of claim 8 furthercomprising using a third bottom form roll and a third top form roll toperform the third rolling stage.
 10. The method of claim 9 wherein formrolling the cylinder such that the flanges are folded about the ends ofthe magnetic material in a final position further comprises form rollingthe cylinder during a fourth rolling stage.
 11. The method of claim 10further comprising using a fourth bottom form roll and a fourth top formroll to perform the fourth rolling stage.
 12. The method of claim 3 or11 wherein the form rolling stages are performed using a form rollingmachine.
 13. The method of claim 3 or 11 wherein welding the ends of astrip of sheet metal comprises welding the ends of a strip of stainlesssteel.
 14. The method of claim 1 further comprising cutting the cylinderabout its entire circumference at two axial locations prior to formrolling thereby isolating a remaining central portion of the cylinder.